This invention relates to a release system for loads which develop during a torquing process on a backup wrench coupled between a fastener and an adjacent component disposed within a surface, and more particularly to a reaction cam adapted for use with a backup wrench during torquing processes.
A typical torquing process involves torquing a nut located on an end of a threaded fastener with a torque wrench while a head portion of the fastener is grasped with a first end of a backup wrench. The backup wrench is oriented such that a second end thereof is located proximate to an adjacent bolt or component. The first end of the backup wrench holds the head portion of the fastener while a torquing force is applied to the nut. The second end of the backup wrench is allowed to react against the head of an adjacent component to thereby provide a reaction force. The adjacent component typically also has a standard socket placed on the head thereof. A plastic wedge is positioned between the socket and the backup wrench such that the second end of the backup wrench reacts directly against the plastic wedge. Once the nut has been sufficiently torqued, the plastic wedge is removed (typically knocked out with a hammer and flat blade screwdriver) from its tightly held position between the socket and the backup wrench to release the load being applied by the backup wrench to the adjacent component.
Some fasteners, however, are located in configurations which make it difficult or impossible to easily use the above-described torquing process. For example, when using adjacent component heads on pipe flange fittings or rear spar terminal fitting bolts to provide the fixed, reacting element, it can be difficult, because of space constraints, to knock out the plastic wedge after the torquing force has been applied and the backup wrench is held tightly against such reacting element. In addition, the removal of the tightly held plastic wedge in the typical torquing process may damage the reacting element due to the difficulty of removing the plastic wedge. Furthermore, the use of multiple components to form the reacting element, such as a socket and a plastic wedge, is undesirable because such components can be easily lost in the work environment. This can be particularly problematic in machinery, engines and other apparatus with moving parts which are highly susceptible to jamming or damage from extraneous parts.
It is therefore a principal object of the present invention to provide a reaction cam that is capable of operating in configurations where it is difficult to use a conventional plastic wedge between an adjacent socket and backup wrench as the means to remove the reaction force applied to the backup wrench.
It is another object of the present invention to provide a reaction cam which does not damage the adjacent component with which it is engaged when a backup wrench is utilized in a torquing process.
It is another object of the present invention to provide a reaction cam which does not have multiple pieces which can easily be separated and lost in the work environment.
The above and other objects are provided by a reaction cam in accordance with a preferred embodiment of the present invention, and a method of using same. The reaction cam is used on a fixed component disposed adjacent to a threaded fastener being torqued. The reaction cam provides the reaction force on a backup wrench as a torque is applied to one element of the threaded fastener, while the backup wrench is coupled to a second element of the fastener. A principal feature of the reaction cam is that the reaction cam protects the adjacent component by receiving the force applied by the backup wrench that abuts the reaction cam, while allowing one component of the reaction cam to be easily moved after the torquing process is completed, to thus allow the reaction cam and the backup wrench to both be easily removed.
The reaction cam includes an inner sleeve disposed within a cam housing having an eccentric opening. The inner sleeve is placed on the head of the adjacent component. The cam housing is rotatably supported about the inner sleeve. The cam housing includes a drive opening which can be engaged with a drive element of a conventional socket wrench and rotated.
Under loaded conditions caused by torquing the nut of the fastener, the backup wrench abuts and applies a force to the cam housing. The reaction cam system applies a counter-acting reaction force to the backup wrench which allows the nut to be torqued without the threaded fastener turning. Under a fully loaded condition, the drive opening in the cam housing can be easily engaged with a drive element of a conventional socket wrench and rotated. The eccentric opening causes the cam housing to move eccentrically about the inner sleeve. This allows a small gap to be created between the backup wrench and reaction cam, and the reaction force applied by the system is thus removed. The backup wrench can then be easily removed from the fastener head. The reaction cam of the present invention can then also be easily removed from the adjacent component. Furthermore, the reaction cam of the present invention protects the adjacent component and fittings from damage.